(1) Field of the Invention:
This invention relates to fluid powered pumps and motors and adjustable speed drives and piston powered drives of the type utilized in industry for speed drive applications.
(2) Description of the Prior Art:
Prior art devices of this type have relied on a number of different design drives with a plurality of radially positioned hydraulic pistons. See for example U.S. Pat. Nos. 1,943,637, 2,870,747, 3,120,154 and 4,242,068.
In U.S. Pat. No. 1,943,637, a high pressure rotary engine is disclosed having a piston drum with multiple pistons extending therefrom, the ends of which are slidably engaged in guides in an annular groove within the inner surface of a casing.
U.S. Pat. No. 2,870,747 shows a hydraulic motor having a rotor with radially positioned spring loaded rollers that engage a track and are moved relative thereto by fluid pressure.
U.S. Pat. No. 3,120,154 discloses a hydraulic motor having a rotor with radially positioned piston and vane assemblies that are held against the interior of the housing by a shaft. Input of fluid pressure against the vanes rotates the rotor.
Finally, in U.S. Pat. No. 4,242,068, a vane pump is shown wherein a by-pass port in the vane provides a path to the low pressure zone behind the vane during the time the vane is exposed to high pressure.
Applicant's device is an adjustable speed drive having a plurality of radially positioned pistons and roller assemblies that drive a movable cam ring thereby transmitting and controlling power from an input shaft to an output shaft by means of controlling fluid flow and pressure from piston assemblies.